Clutch



Patented May 24, 19.32-

UNITED STATES .PATENT oFFcE LEROY T. rUTsoHER, or MINNEAPoLIs,MINNEsOTA, AssIGNon To EDWIN n. BENMAN, Y OF MINNEAPOLIS, MINNESOTA f fCLUTCH Application led October 1, 1930,v Serial No. 485,670.l

My invention has for its object the provision ofan extremely simple andhighly eficient centrifugal force friction clutch and,

to this end,`it consists of the novel construction and arrangement ofparts thereinafter described and defined in the claims.

This improved clutch, while intended for general use, is especially welladapted as a` driving Connection between an electric motor and positiveoperatlng connections for opening and closing garage-doors and thelike,-where the action'of the load is stiff and l difficult to start dueto the weightl thereof and in such cases the clutch will permit the l.15 Ymotor to build up a speed and gradually pick up the load. Thisaction of the clutch permits the motor to overcome its static fricl tionand the inertia of the load with a smooth action.

The invention further provides a clutch that is so evenly balanced inits action as to make the same especially well adapted for usein theoperating connections formechanism wherein, it is essential thatvibration,

26 produced by setting and releasing the clutch, is reduced toa'minimum. v

In the accompanying drawings, whichillustrate the invention,` likecharacters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a fragmentary view'in elevation showing the improved clutcharranged to connect the rotor shaft of an electric motor to a shaft tobe driventherefrom;

Fig. 2 is a view partly in Aelevation and partly in section taken on theline 2 2 of Fig. 1, on an enlarged scale; f

Fig. 3is a View principally in sect-ion taken onthe line 3-3 ofFig. l2;and

Fig. 4 is a viewy correspondingpto Figp?) but showing a different typeof weight in the shoes. d A

The numeral 5 indicates an electric motor and the numeral 6 indicatesashaftv axially aligned with the rotor shaft of said motor.

The improved clutch vcomprisesa driving member in the form of a disk 7and a driven member 8 1n the form offa -drum havmg'an annular internalshoe-'engaging surface.

Formed lwiththe outer, face of the clutch y member 7`V is an outwardlyprojecting hub 9 and formedfon theouter face of the back of Y ,thedrum-8 is a hub 10. :Bothhclutchmem- `hers 7 and 8 are mounted on theshaft 6 which holds the same inV true axialalignment rand againstangular 'or wobble movement in Y respect to each other. TheV clutchVmember 7 1s loose on the shaft Gand the drum 8 is rigidly securedthereto by a set-screw 11 that "has.'threadedfengagement with'the Vhub10 and impingesagainst said shaft, see Fig-.3.

y A flexible coupling 12, ofwell-known 4commercial' formh connects therotor shaft of the motor` tothe 4,shaft 6. Thiscoupling 12 includes afibre disk l'having on each vface a diametrically extended tongue 14andthe two tongues 14 extend at right angles to each other. Onepof thetongues :14 loosely vextends into a groove in the outer endof a hub 15rigidly secured bya set-screw tothe outer end'of the rotor shaft of theVmotor 5 and the other tongue 14v loosely extends into a groove in theouter end of the hub 9.j

`Cast on theinner face of theV clutch member 7 is a vpair of parallelperpendicular flanges 16 which are laterally spacedto form, togetherwith said clutch member, a diametrically extended channeled way or shoeguide 17 the ends of which terminate substantially 17 at diametricallyopposite points from the shaft 6. Each shoe 18 is in theform of a block,theouter end of which'is on acurve having the sameradiusas the internalsur- 't face of the drum 8` for frictional contact therewith `throughoutthe entire area thereof. The inner ends .of the shoes 18 are notched toafford vclearance for the shaft' and permit the required radialmovements of said shoesin the way 17;

The drum 8 is preferably mademfrom cast 'the shoes 18 is such that they:freely move in f thevwayr17 and betweenthefclutch member v at theperiphery of said member. A pairof 50 A i loose` shoes ,18'are'looselymounted 'in the way 7 and the back of the clutch member8 but at the sametime, are held thereby against such Y angular movements in respectthereto that tional contact with the drumv 8. shown,

the weights 19 are embedded inthe shoes 18 so that they dol not come incontact with either the. clutch member 7, drum 8- or the flanges 16. l

Figs. 2 and 3 show each shoe 18provrided with two weights 19 cach'ofwhich is in the f formi cfa round metalrbar mounted in a borelike cavity20 which entends into said shoe from one edge thereof, and is securelyheld therein by friction or otherwise. The

Weights 19 are. of the same weight and their positions in the shoes18--are exactly the same so that the action of said shoes on the drum 8,at diametrically opposite points under'the action'of centrifugalforce,is the same; or, inJ other words, these equally balanced shoes `18L moveat the same rate of speed and' force during the setting and. re-

leasing of the clutch, .and hence, prevent vi brations in the clutchthat'would` otherwise be producedk byfthe'acontact 'of thehshoesy 18with the vdrum. 8 andv thereleasing of the same therefromy at differenttimes and: under unequal pressure. Furthermore, by holding` thefclutchkmembers 7 and 8 in true axial alignment, which is' accomplished as shownby mounting said' members on the same shaft,

lmaterially assists the equally balanced shoes 18V in accomplishing theresult desired. The Weights 19 in each shoe 1-8 are laterally spaced'radially fromthe aX-is of the shaft 6 and their axes are in the planeofrotation of the clutch andl at right angles to the direction oftravelY of said' shoesin the way 17.

Fig. 4 shows a' structure identical with that shown' in Figsizl, 21 and3y and ythelparts thereof havethesame reference characters except astothe weights which are designated by the numeral V20; The weights 20,.shown in Fig. 4, are variable and shiftable in the shoes 18. Theseweights 20 eachy include a body madeV up of a multiplicity ofV shotloosely held confined in a cavityr- 21 formed inthe respective shoef18and closed by a stopper 22 `preferably of the same materialV as theshoe.

The shiftableweights 2() move outwardin the cavities` 21 underLcentrifugal force lduring the rotation ofthe clutch`member17 by therotor shaft of the motor 5 and tightly press the shoes 18 against thedrum 8.y These weights 20 may be varied, at will, by removing part ofthe shot or adding other shot thereto. By forming the weights 20 eachfrom the same number of shot, said weights will be equally balanced.Thel two cavities 21in each shoe 18 have'their axes spaced equidistancesfrom the centers of said shoe both as to thickness and width thereof.

Operation ofclatch Under normal conditions the impro-ved clutch willcarry a load up to the speed of themotor in the same manner as anordinary direct connected drive.

However, in case the loadis, stiff: or difficult to'start due tofweight,therclutch is` de-l signedy to permit thev motor to build upa i speedand then pick upzthe load` gradually,

and as previously state-d, this tends first,to overcome the staticfrictionofthe. motor and' thereafter,.when the speedof. the motor" hasbeen built up, overcome the inertia lofthe load with aV result that theload. is'easily started with asmooth action. y Y A very importantfeature is thatit tends-to keepthe starting current of the motor down sothat Vthere is nofexcessive starting current on a heavy' loadvwhichprotects the motor and permits the proper, fusing` thereof. i

The action of the clutch The driving clutch member 7 being'fast on therotor shaftrof the motor 5 is free to.

turn `within the drum 8 when the motor 5 vis at rest or,xwhen turned byhand power is transmitted from the drivingy member through the shoes 18to the drum 8. When the current is applied to the motor5 the clutchmember 7 .and shoes 18 rotate within the drum 8 for lan instant beforethe speed reaches a Vpoint atY which theshoes18engage of. this iut-Ch".ion

the' drum 8. As the speed of the motor 5 increases, whichr ity does veryquickly, the cen-v trifugal force of the shoes18 overcomes therestraining force of the load. If the load can be started readily thespeed continues tofincrease until. a maximum speed'. and centrifu galforce ofthe clutchis in action.

son and requires high initial torque to set it in motion the actionv isdifferent. In this case, since the characteristic lof the loadpreventsthe drumfrom turning freely, the-fric- -tionV betweenthe shoes 18 and.the d'rum8` slows the motor down to a speed lat which thecentrifugalforce of the shoes 18 is overcome and. allows the clutch/toslipor release. The motor 5 then comes up to speed. again and theshoes18r engage the `drum 8.` This However, if the load is stiff for somereaaction takes place very rapidly and since the shoes 18 come incontact with thel drum 8 very quickly a highv torque is transmittedtothe load. rllhe intensity of this action iss.

increased until the heat generated by the friction of the shoes 18 onthe drum 8 increases a coefficient of friction by said shoes and drum toa point Where the entire kinetic energy of the motor 5 is transmitted tothe load. The result is a starting torque many times greater than fullload torque suiicient to start even the most obstinate load.

On a heavy load the action continues until the load is started or untilthe load overcomes the centrifugal force and holding power of theclutch, Without damaging the clutch or equipment.

What I claim is:

l. A clutch comprising a driving member and a driven member, onek ofWhich is a drum and the other of which is provided vvitha singlechanneled shoe into the drum and substantially the full diameterthereof, and a pair of loose shoes loosely held by the guide for contactwith the drum at diametrically opposite points and subject tocentrifugal forceduring rotation of the respective member.

2. The structure defined in claim 1 in which the shoe is block-like andits Width is slightly less than that of the guide.

3. A clutch comprising a driving member and a driven member, one ofwhich is a drum and the other of Which is provided With a shoe guideextending into the drum, a loose shoe loosely held by the guide Vforcontact with the drum and subject to centrifugal Vforce during rotationof the respective member, and a cylindrical Weight in the shoe whichextends radially thereof.

4l. The structure defined in claim 3 in` short of the outer end of theshoe and isy covered thereby.

5. A clutch comprising a driving member and a driven member, one ofwhich is a drum and the other of Which is provided with a shoe guideextending into the drum, a loose shoe loosely held by the guide forcontact with the drum and subject to centrifugal force during rotationof the respective member, and a pair of Weights inthe shoe laterallyspaced eircumferentially of the drum and positioned equal distances fromthe transverse center of the shoe.

6. The structure delined in claim 5 in Which the Weights areindependently variable.

7 A clutch comprising a driving member and a driven member, one of Whichis a drum and the other of which is provided With a shoe guide extendinginto the drum, a" loose block-like shoe loosely held by the guide for ashiftable Weight in each chamber subjectv kto centrifugal force duringrotation of the guide Which extends chamber subject lto centrifugalforce during rotation of the respective member. p

8. A clutch comprising a driving member and aT driven member, one ofwhich is a drum and the other of` which; is provided With a` shoe guideextending into the drum, a loose j shoe loosely held by theguide forcontact with the drum and subject .to `centrifugal* force duringrotation of the' respective mem ber, said shoe having tvvo closedinternal chambers laterally spaced circumferentially of the drum andpositioned equal distances from the transverse center of the shoe, and

respective member.

9. The structure defined in claimV 8 -in Which each Weight is'individually variable.`

lO. A clutch comprising a driving member and a driven member, one ofwhich is a drum and the other of Which is vprovided With 'a pair oflaterally spaced parallel flanges arranged to form a single radial shoeguide Which extends into the drum and substantiallyl the full diameterthereof, and a 'pairof loose block-like shoes loosely` held by v.theguide for contact with the drum at diametrically opposite points andsubject to 4fcenl trifugal force lduring rotation of. the respectivemember. Y Y

ll. A clutch comprising a driving member and a driven member, one ofwhich 1s a drum and the other of which is a disk forming one of theheads of the drum, each of said members having an external hub forsecuring the 100 same to a shaft, said diskV having on its inner face apair of laterally spaced parallel flanges arranged to form a singleradial shoe guide which extends into the drum and substantially the fulldiameter thereof, and a pair i of loose block-like shoes loosely held bythe contact With the drum and subject to cen-l trifugal force duringrotation Vof the Vrespective member, said shoe having a closed internalcylindrical chamber which extends radi-` ally thereof, and a shiftableWeight in the so Y

